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Comments: 278 +- Technology: Berkeley Engineers Have Some Bad News About Air Cars on Saturday November 21, @02:31PM
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timothy
on Saturday November 21, @02:31PM
from the puff-the-magic-dragon-was-involved dept.
from the puff-the-magic-dragon-was-involved dept.
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cheeks5965 writes "We've argued before over compressed air vehicles, a.k.a. air cars. Air cars are an enchanting idea, providing mobility with zero fuel consumption or environmental impacts. The NYTimes' Green Inc. blog reports that the reality is less rosy. New research from UC Berkeley and ICF International puts a period at the end of the discussion, showing that compressed air is a very poor fuel, storing less than 1% of the energy in gasoline; air cars won't get you far, with a range of just 29 miles in typical city driving; and despite appearing green the vehicles are worse for the environment, with twice the carbon footprint as gasoline vehicles, from producing the electricity used to compress the air. Given these barriers, manufacturer claims should definitely be taken with a grain of salt."
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"zero fuel"? (Score:2, Insightful)
Re: (Score:3, Informative)
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Ugh? I suppose if I connected the bottom of a tank, to the top of itself -- it'd explode (from infinite pressure?).
(What ever pressure you gain from going down, you'll lose by going back up (with your connecting tube)
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Re: (Score:3, Interesting)
Get a deal for 100 megawatts at 50KV, line saturated to 70% of its capacity 24/7 except holidays,
Get a deal for 10 kilowatts at 110V saturated to 40% of its capacity in the evenings and 10% the rest of the time.
See how much you pay for KWh in the first case, how much in the second case.
Bulk trade rules apply to electricity much more than to normal goods.
Also, check how much a solar panel costs. About $1000/100W.
Considering about 15 cents/KWh energy, that's 1.5 cent/hour you save. That's 7.5 years for return
Re: (Score:3, Informative)
I just checked these numbers. They are quite accurate, but interestingly, the difference is made up of almost entirely of taxes. The power company adds less than 10% to the spot price, so bulk seems to have little to do with it.
In my case the price is 9.33 euro cents per kWh. This is made up of:
Spot price: 3.81 cents (41%)
Added by t
Re: (Score:3, Informative)
I used a table very similar to this one (but yearly instead of monthly)
http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_a.html [doe.gov]
15 US cents seemed to be about the average residential price, 4 cents was the low of the industrial - and considering the massive bulk purchase, the lowest pick seems fair here.
The $1000 was the first google hit for 100W solar panel.
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At least they don't pollute the city directly (Score:5, Insightful)
Re:At least they don't pollute the city directly (Score:5, Insightful)
What benefits do these air powered cars have that aren't significantly exceeded by electric vehicles?
The range of these cars is 1/5 of electric cars *and* is less efficient.
Parent
Re:At least they don't pollute the city directly (Score:5, Informative)
They were first developed to be used in environments, where sparks could lead to an explosion (e.g. chemical plants or refineries). There you can't use electric cars.
Parent
Re: (Score:3, Insightful)
Yeah but how many people actually need a car that is specifically designed for those kind of environments? They fill a very limited niche that doesn't seem to overlap all that much with most peoples' driving needs. The range is far too short.
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They were first developed to be used in environments where sparks could lead to an explosion
Compressed air engines were used in sealed, oxygen-deprived, environments: mines, tunnels, refrigerated storage plants and so on.
They could be quite practical as switch engines.
Larger and more powerful than you might expect. You'll find some pictures here:
INDUSTRIAL LOCOMOTIVES FOR MINING, FACTORY, AND ALLIED USES PART. II. COMPRESSED AIR AND INTERNAL COMBUSTION LOCOMOTIVES [tinyworld.co.uk]
Re:At least they don't pollute the city directly (Score:4, Informative)
To actually get an asynchronous motor in a car working and to control the speed you need some sophisticated electronics which weren't available when the gas pressure cars were initially developed.
Parent
Re: (Score:3, Interesting)
These were also the same environments that fireless steam locomotives were used in. The hot water stores a lot more energy for a given volume than compressed air.
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To power the air compressors, you'd need more power plants. Many more, since compressed air isn't efficient. Moreover, the compressors themselves would be dirty, so "free A/C" would be unhealthy.
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bad news about bad news (Score:3, Insightful)
Since when does a conclusive study demonstrating what you already knew was true constitute "bad news"?
Bad news: perpetual motion doesn't exist. Would it be good news if it did exist? With such a toy, an enterprising galaxy could tip the universe toward heat death. Maybe a supernova is just perpetual motion gone Sorcerer's Apprentice.
If you're in a troubled relationship and you finally have a big blow out argument, and one of you storms off into the night, is that bad news, or good news? If you defined k
Replace compressed air with compressed hydrogen (Score:2)
Problem solved. Now you not only get energy from the potential energy of the compression, but also from the fuel itself.
Zero Emissions are worse?? (Score:3, Insightful)
and despite appearing green the vehicles are worse for the environment
Compressed air is just a medium in which to store energy. The energy could come from solar panels on your garage. It compresses the air. The air powers you car. Zero emitions.
This is opposed to batteries which really aren't good for the environment, but all those Prius owners don't really seem to care about Lithum strip mines while patting themselves on their backs.
Hydrogen is yet another method of storing energy.
Just compressing air from solar, wind power, etc gives Zero emissions no matter if the efficiency is only 1% or 100%
Re:Zero Emissions are worse?? (Score:5, Insightful)
Those solar panels, wind turbines, penis pumps etc had to be manufactured somehow and that manufacturing process creates emissions. "Carbon offsets" is a joke, wake up people! Any emission is an emission.
Parent
Re:Zero Emissions are worse?? (Score:5, Funny)
"Carbon offsets" is a joke, wake up people! Any emission is an emission.
I hold all my farts in sir!
Parent
Re:Burning wood is not zero emission (Score:4, Insightful)
As said in great grandparent post, compressed air and hydrogen are energy storage mediums. Wood is the same thing. Trees use solar energy to convert CO2 into carbon. When you burn the wood, you put the CO2 back into the air and get the energy back as heat.
It doesn't matter if we burn the wood for something useful, the trees dies and rots, or the tree is burned in a forest fire: at some point the carbon is coming back out of that tree.
Parent
Re:Zero Emissions are worse?? (Score:5, Informative)
>>>all those Prius owners don't really seem to care about Lithum strip mines
Prius cars don't use lithium. They use nickle and hydride, and when disposed are no more harmful than throwing-away coins and water. (Although recycling the metal would be better.)
Parent
Re:Zero Emissions are worse?? (Score:4, Interesting)
i'm curious as to how much thought you're really given to this, above and beyond the 'mythbusters' level. firstly, you're right, Priora are not built with lithium batteries, though you should wish that they were. Lithium is NOT stripmined, Lithium salts are extracted from the water of mineral springs, brine pools and brine deposits. The metal is produced electrolytically from a mixture of fused lithium and potassium chloride. Nickel on the other hand IS strip-mined and while their disposal may not be all that bad, the production of nickel batteries is extremely harmful to the environment. IIRC there is a mine in Canada used for the production of Prius batteries, if thats the one i'm thinking it is, there is a 60 mile dead zone around it which contains about as much life as the surface of the moon.
there are of course problems with most forms of energy storage, the trick is finding ways to manage those problems.
Parent
Re: (Score:3, Informative)
The nickel mine you are thinking about is probably Inco's mine in Sudbury Ontario. There is indeed a dead zone, but it is not a strip mine, the mine is underground. The dead zone is the result of acid fallout from the smelter. After killing off the area, and facing criticism, Inco built what was then the world's largest smokestack in the early seventies. The smelter still belches sulfur compounds, but now they are dispersed over a much larger area.
Much of the area still looks like a moonscape.
http://en.wiki [wikipedia.org]
Re: (Score:3, Interesting)
Citation? I did a little googling, and it doesn't appear to be a hot topic by any standard. The biggest problems with nickel seem to be in its production, not its disposal, and I didn't see any references to nickel toxicity itself.
Plus, we're talking about battery disposal here. The odds are much better that they'd be dumped in landfills than that they'd be dumped in rivers, lakes, and oceans. With landfills, you'd be more worried about aquifer pollution, and I didn't see much concern there, either.
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It said 'worse for the environment'. Using more energy is worse for the environment and will continue to be until ALL our energy comes from clean sources.
<blockquote>This is opposed to batteries which really aren't good for the environment, but all those Prius owners don't really seem to care
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You , sir, are the definition of idiocracy. Where the uninformed feel the need to speak out incorrectly and grossly misinform others.
Take a solar cell on your roof. Power a compressor hooked up to your air car. Take the same solar cell and the next
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Compressed air is just a medium in which to store energy. The energy could come from solar panels on your garage. It compresses the air. The air powers you car. Zero emitions.
Okay, smart guy. Explain to us the zero-emissions process for manufacturing those solar panels, your air compressor, and your air car.
We're waiting.
Re:Zero Emissions are worse?? (Score:5, Funny)
Parent
You should use two measures of electric vehicles (Score:5, Interesting)
The significant fact about electric (or hydrogen fuel cell), or electrically compressed air vehicles
is that electricity (and hence hydrogen via electrolysis, or compressed air tanks) can be generated
in all manner of relatively or completely "green" ways, whereas fossil-fuel transportation is
at least presently restricted to getting its fuel by digging up stored carbon from the Earth at
unsustainable rates.
So electric vehicles (or hydrogen fuel cell, or even relatively inefficient compressed air) vehicles,
are stepping stones on the path to a non-GHG producing future energy system.
So the "green-ness" or carbon footprint of these electrically based technologies should be
measured with two separate baselines:
1. What would their carbon footprint be if all electricity was generated with carbon-neutral generation
methods such as wind/solar/geothermal/hydro/wave/nuclear.
2. What is the carbon footprint assuming the US continues to maintain arguably the most carbon-dirty
electrical generating mix in the world.
Measured in this light, it can be seen that the complete issue is changing the electrical power source for the
US, in parallel with adopting one or multiple forms of transportation technology that is electrically based.
Either change without the other does not work. Both are necessary for effective improvement in emissions
reduction of transportation.
I guess congratulations are in order (Score:4, Insightful)
I mean really. There's perfectly good reasons why we're not using compressed air as a 'fuel', and it's not that we hadn't thought of it. The idea (and applications) have been around since the 19th century.
Re:I guess congratulations are in order (Score:5, Insightful)
The problem of humanity is one of the capture, storage, and application of energy.
Gasoline is a fantastic medium for energy storage: it's a better battery than any battery we know how to cheaply produce and service, and that's why we use it. But the energy capture function for gasoline [getting the energy into the gasoline] sucks. And the energy dispersal/application of gasoline has some environmentalists pretty upset.
Nature gives us many ways to store energy now and release it later. The chemical combustion of gasoline is one such mechanism. The desire of a compressed gas to push forcefully against its container is another such mechanism. The strong nuclear bindig energy is a particulary potent and pervasive mechanism. The specific heat of water is yet another.
The fundamental mechanisms of energy storage have been known about for a long time. Taken as a complete system to let humanity accomplish some goal, we are concerned with how we capture the energy, how much of it we can store [and at what cost], and how easy it is to get it back out in a form condusive to the sort of work we want to do with it.
As technology changes we must continually re-evaluate the end-to-end story for a particular aqcuisition/storage/application energy cycle. We may find that we are willing to tolerate a 100 fold decrease in energy storage performance for a 200 fold increase in acquisition efficiency and a qualitative improvement in application performance.
For instance, if i live in arizona and i have a sterling-engine powered air compressor that pumps my 50G tank to 100psi after 12 hours of sunlight, and this lets me go about 10 miles with no consumption of anything other than sunlight... I'm interested. If i commute 5 miles each way, I can get to work and back using nothing but solar energy. And unlike with PV panels and electrical batteries, a guy with a pipe threading die and a welder could build refueling system in his garage, out of stuff that has zero environmental impact whatsoever.
I think that's cool. I'm obviously playing fast and loose with the numbers. Since the kJ/m^2 of solar radiation is known at gridsquares all over north america, you could actually make some ballpark efficiency guesses about peices of the process and plug in real numbers to my hypothetical example. Even if reality is 1 mile @ 30mph after 8 hrs of sunlight.. that fits _some_ usage profile.
It used to be that every farm in North Dakota [where I live] had a windmill powering the farm. Then they disappeared and became an anachronism paying homage to a bygone era. Now windmills are dotting the countryside again. It didn't get windier here.
What changed?
The physics of energy capture, storage, and dispersion have always been the same; our efficiency and the context of the problem space continue to change. As such we must constantly re-evaluate what we did in the past against the realities of today.
Parent
Cold Steam Engine? (Score:3, Interesting)
It occurs to me that a compressed air vehicle could be compared to a "cold" steam engine.
Have there been any scientific advances that could make steam engines in general viable for car sized engines?
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more than a century ago [wikipedia.org].
http://www.conceptcarz.com/vehicle/z11210/Stanley-Steamer-Rocket.aspx [conceptcarz.com]Powered by a steam engine, and did 150 mph back in 1907.
compressed air uses (Score:5, Informative)
I think compressed air cars will serve a specialist role, operating in specific roles. Whether there is commercial visbility, I do not know. Aside from the modern buzzword of "Footprint", the technology to compress air is as old as stem and pistons. That wont change. Even on high tech air craft carriers, the landing restraints have huge hoary old compressed air pistons dampenening the jets planes. The tech below deck, keeps the ram clean and applies some lubricant periodically....just as would happen in steam train days.
Time for a new tagline (Score:5, Funny)
Slashdot - news for idiots, stuff that's obvious
No kidding? (Score:5, Insightful)
This is a surprise to someone? Who ever though this *could* work? Certainly not anyone with any knowledge of thermodynamics. The only compressed -gas systems that even have a chance of working are those that store the working fluid as a liquid, meaning it has to be able to be liquified at room temperature at a reasonable pressure (few hundred PSI at most). Otherwise the tanks are huge and heavy (meaning it will barely move under power) or they are small and heavy (meaning it has no range). Two excellent working fluid for this purpose are - wait for it - CO2 and Freon! Oops.
Brett
There are other ways to compress the air. (Score:4, Interesting)
Compressing air can be done with any source of mechanical energy. Put a windmill on your roof, gear it down, and have it drive the compressor directly.
Come to think of it, having a sizable amount of compressed air storage in one's house would be handy. Great for dusting.
-jcr
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Sounds like a tech geek's way of looking at it.
Most people would say -- having a sizable amount of compressed air storage in one's house is great all around -- for your pneumatic power tools.
Re:There are other ways to compress the air. (Score:5, Insightful)
But you could just as easily have that windmill power a turbine to generate electricity to charge the battery in your electric car and get a far higher energy density leading to more mileage per charge and per each day's wind. I think that's the point that's being made. There's lots of clean ways that can generate energy -- any of which can be used to compress air, but why add that extra unnecessary step in the middle when it's just an added inefficiency?
Parent
Time to fish out the calculator (Score:3, Interesting)
Compressing air can be done with any source of mechanical energy. Put a windmill on your roof, gear it down, and have it drive the compressor directly
Translate this into practical terms.
Give me an estimate of the air car's speed, range, weight of cargo, weight of passengers.
Tell me how long it will take to refill the tank.
I was greatly disappointed by the lack of hovering (Score:4, Funny)
"...Air Cars" is an amazingly deceptive headline :(
Oh thank [insert deity here], (Score:4, Funny)
Technology transfers poorly from guitars (Score:4, Funny)
I own an air guitar and it's actually pretty sweet - I can make like I'm rocking out wherever I am. Whereas an air car ... I don't see the market. You're at a party and the music's pumping and you just decide to "air drive" to the shops? Not cool.
Blows... (Score:3, Insightful)
Using a mechanical air pump driven by the wind makes massive sense to me, it is patently obvious. This method alone makes air power a win.
How we generate energy now for air cars now makes no sense, is patently stupid. Fossil fuel -> heat energy -> mechanical energy -> electricity over a lossy inefficient grid -> pumping compressed air -> filling up your car.
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Unfortunately its not a googlewhack: Results 1 - 10 of about 2,550 for dompressed